The present invention is directed to a gas laser with a laser gas circulating system in which there is a fan which moves a laser gas through the gas laser discharge tube or space and through a cooling system.
Such gas lasers are known in many forms and embodiments. The laser gas is circulated by the fan in such gas lasers and moved to and through the laser discharge space. In addition, the laser gas is fed through a cooling system in which the heat generated in the discharge space and by the fan is extracted from the gas. Particularly in a high performance gas laser, there are correlations between the characteristic variables of the laser, such as, for example, the beam diameter, the beam quality, the laser length, and the laser discharge space which will include its geometry, i.e., the diameter and length of the discharge tube, the gas pressure, the gas temperature, the efficiency of the laser, the flow resistance, the gas throughput, etc.
In order to be able to achieve optimum results, the fan should be coordinated with these variable characteristics of the laser. However, if the laser and the fan are coordinated with one another by setting the variable characteristics of the laser or the characteristic variables of the fan, this may apply to only one of the laser's operating states. However, some characteristic variables cannot be set, including the diameter of the discharge tube for example. A change can take place here only by changing the tube.
In designing the laser, one must try to reach the operating point on the fan curve where there is the greatest possible gas throughput. The fan curve is understood as the connection between the pressure quotient .PI.=P.sub.pressure /P.sub.suction and the volume current Vo of the fan. Based on the characteristic data (geometry of discharge space), it is possible that the operating point does not lie in the optimal range. Also there is always the risk in lasers with very high flow resistance, that the fan no longer blows or goes into an operating state in which the fan's blowing capacity fluctuates.
It is an object of the invention to provide a novel gas laser in which the volume flow of gas through the laser is increased without changing its basic components.
Another object of the invention is to provide such a laser in which there is an additional flow path for a volume of the gas.